package com.kaigejava.facademode;

/**
 * Created by kaigejava on 2019/9/2.
 * 屏幕
 */
public class Screen {
    private static Screen instance = null;

    private Screen() {

    }

    public static Screen getInstance() {
        if (instance == null) {
            instance = new Screen();
        }

        return instance;
    }

    public void up() {
        System.out.println("Screen  up");
    }

    public void down() {
        System.out.println("Screen  down");
    }
}
